This invention pertains to a screw compressor. The invention preferably, but not exclusively applies to a screw compressor used to produce a pressurized air stream for pneumatic transport of bulk materials. In particular, the invention applies to a screw compressor designed to be attached to a silo vehicle.
Screw compressors are air compressors that work on the positive displacement principle. They have advantageous characteristics as compared to other compressors that make them especially suitable for the pneumatic transport of bulk materials. This applies in particular for so-called dry-running screw compressors in which the screw rotors, which are synchronized by means of a synchromesh gear, do not make any contact with each other nor with the surrounding housing parts. Thus, there is no need for lubrication in the compression space so that this space can be kept oil free, preventing any oil contamination of the pressurized air. Also, since the rotors run without touching one another, there is no wear in this area that could reduce their lifespan. No abrasion arises that can contaminate the conveyed air. As a result of their operating characteristics, screw compressors are suited mainly for the achievement of high compression ratios. They are insensitive to short term pressure increases that could be caused by pluggage of the pipelines carrying the pressurized air. Finally, they are lightweight and compact, which makes them suited especially for mobile use, for example in silo vehicles.
In a known screw compressor of this type, the compressor housing beneath the two rotors is designed as an oil pan. This has the disadvantage, among other things, in that a strong thermal coupling between the compressor space and the oil supply container arises so that the oil in the supply container is heated up to a considerable degree due to the heat produced in the compressor space as a result of the compression.
The purpose of this invention is to construct a compressor housing with as much of a thermal separation of the oil supply container from the actual compressor space as possible overall.
The construction according to the invention, wherein the rotor housing and the supply container project out from the pedestal shaped drive housing separately and essentially parallel to one another, results in a significantly reduced heat transfer from the rotor housing to the oil supply container. This creates the advantageous ability of keeping the xe2x80x9clanternxe2x80x9d, or the opening of a ventilation channel that leads away from the pressurized bearing area of the rotors, especially protected.
One embodiment form of the compressor according to the invention is explained in more detail with the help of the drawings.